Vibratory compactors or drivers are in common use in the construction industry for compacting loose soil such as that from dug up trenches and the like, or for sheet or pile driving purposes. The term vibratory compactor as used hereinafter is intended to also include vibratory drivers. Such vibratory compactors or drivers are generally comprised of a closed housing mounted by rubber shear mounts for vibratory motion within and with respect to a support frame which is pivotally mounted in depending relation on the free end of the boom or work arm of a carrier machine, such as a backhoe or excavator, for pivotal movement in the vertical plane of the boom. Fixedly secured in a horizontal position to the bottom of the housing, in a position lying clear of the lower end of the compactor support frame, is a flat rigid metal impactor plate or base plate adapted to be pressed downwardly by the boom against the soil to be compacted, or against the sheet or piling to be driven into the ground, while the impactor plate and its support housing are vibrated at a rapid rate. The vibratory motion of the unitary impactor plate and support housing is imparted thereto by a relatively heavy eccentric mass member which is rotatably mounted within the housing, by roller bearings seated therein, for rotation at a relatively high speed about an eccentric horizontal axis by a hydraulic motor mounted on the housing. The rapidly rotated eccentric mass causes the entire compactor housing and impactor plate to vibrate at a high rate, thereby effectively compacting the loose soil or driving the sheet or piling engaged by the impactor plate.
Because of the eccentricity of the rotating load and the resulting high bearing forces applied to the support bearings for the eccentric mass, adequate lubrication of the support bearings is critical. Two methods of lubrication of these support bearings have been employed in the past. One method involves the use of a grease fitting for each of the bearings for the eccentric mass. Because lubrication of the support bearings is so important, an aggressive daily greasing schedule therefor is recommended. This sometimes results in the entire cavity of the compactor housing becoming filled with grease which not only is wasteful but is detrimental to performance of the compactor in that the grease filling impedes the rotation of and imparts a load to the rotating eccentric mass. Another method of lubricating the support bearings for the eccentric mass employs a bath or filling of lubricating oil in the eccentric housing to a level to be contacted and penetrated by the eccentric mass during each revolution thereof so as to splash oil upwardly out of the body of oil and onto the support bearings. For such purpose, a substantial body of oil is required at all times in the eccentric housing in order to assure that the eccentric mass penetrates the oil body regularly during its rotation and splashes oil therefrom onto the support bearings. Also, elaborate splash directors are required in the housing to redirect the splashed oil upwardly into the support bearings to assure uniform and constant lubrication thereof. Additionally, because the compactor units are often stored upside down, baffling systems and the like to maintain the oil reservoir inside the housing cavity are required.